[mynewt-core] branch master updated: Fix double read on enc_flash driver

[ut...@apache.org]

This is an automated email from the ASF dual-hosted git repository.

utzig pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/mynewt-core.git


The following commit(s) were added to refs/heads/master by this push:
     new 6ddd82c  Fix double read on enc_flash driver
6ddd82c is described below

commit 6ddd82cd5be1057866266094123a64a6148e3071
Author: Fabio Utzig <ut...@apache.org>
AuthorDate: Mon Sep 24 15:15:08 2018 -0300

    Fix double read on enc_flash driver
    
    - Update flash_area_is_empty to use the new hal_flash_isempty_no_buf
      call
    - When enc_flash is testing for an empty flash, now it checks that the
      lower-level driver returned an empty flash already and avoids reading
      data that when it is known to be empty.
---
 hw/drivers/flash/enc_flash/src/enc_flash.c | 13 ++++++-------
 sys/flash_map/src/flash_map.c              | 26 +++++++++-----------------
 2 files changed, 15 insertions(+), 24 deletions(-)

diff --git a/hw/drivers/flash/enc_flash/src/enc_flash.c b/hw/drivers/flash/enc_flash/src/enc_flash.c
index 7f170bf..d2ac9af 100644
--- a/hw/drivers/flash/enc_flash/src/enc_flash.c
+++ b/hw/drivers/flash/enc_flash/src/enc_flash.c
@@ -159,7 +159,6 @@ enc_flash_is_empty(const struct hal_flash *h_dev, uint32_t addr, void *buf,
     struct enc_flash_dev *dev = HAL_TO_ENC(h_dev);
     const struct hal_flash *hwdev;
     int rc;
-    int rc2;
 
     hwdev = dev->efd_hwdev;
 
@@ -167,18 +166,18 @@ enc_flash_is_empty(const struct hal_flash *h_dev, uint32_t addr, void *buf,
         return hwdev->hf_itf->hff_is_empty(hwdev, addr, buf, len);
     } else {
         rc = hal_flash_is_erased(hwdev, addr, buf, len);
-        if (rc < 0) {
+
+        /*
+         * If error or low-level flash is erased, avoid reading it.
+         */
+        if (rc < 0 || rc == 1) {
             return rc;
         }
 
         /*
          * Also read the underlying data.
          */
-        rc2 = enc_flash_read(h_dev, addr, buf, len);
-        if (rc2 < 0) {
-            return rc2;
-        }
-        return rc;
+        return enc_flash_read(h_dev, addr, buf, len);
     }
 }
 
diff --git a/sys/flash_map/src/flash_map.c b/sys/flash_map/src/flash_map.c
index 98c3d35..1a10c54 100644
--- a/sys/flash_map/src/flash_map.c
+++ b/sys/flash_map/src/flash_map.c
@@ -189,25 +189,17 @@ flash_area_erased_val(const struct flash_area *fa)
 int
 flash_area_is_empty(const struct flash_area *fa, bool *empty)
 {
-    uint32_t data[64 >> 2];
-    uint32_t data_off = 0;
-    int8_t bytes_to_read;
     int rc;
 
-     while (data_off < fa->fa_size) {
-         bytes_to_read = min(64, fa->fa_size - data_off);
-         rc = hal_flash_isempty(fa->fa_device_id, fa->fa_off + data_off, data,
-                                bytes_to_read);
-         if (rc < 0) {
-             return rc;
-         } else if (rc == 0) {
-             *empty = false;
-             return 0;
-         }
-         data_off += bytes_to_read;
-     }
-     *empty = true;
-     return 0;
+    *empty = false;
+    rc = hal_flash_isempty_no_buf(fa->fa_device_id, fa->fa_off, fa->fa_size);
+    if (rc < 0) {
+        return rc;
+    } else if (rc == 1) {
+        *empty = true;
+    }
+
+    return 0;
 }
 
 int